Tone modulators operating at varying rates of speed



My 14, 1929; 'J. H. HAMMOND, JR 1,713,126

TONE MODULATORS OPERATING AT'VARYING RATES 0F SPEED Filed March 18, 1927 AT1-URN Eq:

Patented May 14, 1929. i

UNITED STATES JOHN HAYS HAMMOND, JR., OF GLOUCESTER, MASSACHUSETTS.

TONE MODULATORS OPERATING AT VARYING RATES OF SPEED.

Application filed March 18, 1927.

This invention relates to improvements in music modulators and more particularly to the control of tone shading and musical dynamics.

The present invention has particular reterence to a system of tone shading ilior musical instruments of the permissive type, and providesv improved control of musical dynamics in the different parts of the musical scale. It may be employed, however, with equal advantage in connection with any other type of musical instrument where it may be desired to control the tone shadings of the musical scale.

The principal object of the invention is to provide means for modulating and rc- Hecting the sound produced by a musical instrument ditlerently in different parts olf the scale.

A feature olf the invention relates to the provision of a plurality ot modulating reflectors operable at different rates. Another feature relates to the provision o1 improved means foractuating modulating rcllectors at different rates.

Other objects will appear ilrom the lollowing description taken in connection with the accompanying drawings in which- Figure 1 is a plan view and Figure 2 is a front elevation partly in section of a nuisical instrument of the percussive type.

Figure 3 is a sec-tion taken on the line 3 3 of Figure 1.

. Like reference cha actors refer to like parts in the several figures of the drawings.

In the following description and claims,

arts, characteristic 'features and functions will be identilied by specific naines tor convenience of expression, but they are intended to be as generic in their application as the art will permit.

Referring Vto Figuresl, 2 and El ol1 the drawings, there is shown tor the purpose of illustrating one 'form of the invention, a grand piano comprising a casing 10 supported on suitable feet in a conventional manner and having positioned therein a plurality of strings such as 11, 12, and 13, tuned to the notes of the musical chromatic scale. The strings 11 of the left-hand portion ot Figure 2 are assumed to be tuned to the lower notes of the scale and the ings i3 in the right-hand end to the upper notes of the scale, and the intermediate strings such as 12 tuned to the intermediate notes oil the scale. The strings 1 1, 12 and 13 `are Serial No. 176,386.

stretched upon a conventional trame lt and are preferably arranged in a single plane, in the case illustrated, a horizontal plane. A sounding board G0 is provided within the casing l0, in a plane parallel to the plane of the strings.

For each note ot the musical scale there is provided a hammer such as 15, arranged to set into vibration by percussion the strings tuned to the respective note. The strings tuned to notes of low pitch are oilf greater mass than the strings ofhigh pitch, and accordingly the energy produced by the low pitched string is o1 greater intensity .than that produced by the high pitched strings. The strings tuned to cach note oil. the scale are actuated by means of a piano action 16 and a key 17 in a conventional manner. The keys such as 17 are arranged in a manual 18 and may be operated manually in a conventional manner to produce musical sound.

'.lhe casing l() is provided on its inner Vtace with a, layer 50 of sound reflecting material such as a smooth metal sheet. rlhe casing is provided with oppositely disposed controllable apertures in planes above and below the plane ot the strings. For controlling the extent ol opening of these a-pcrtures so asl-to reduce or otherwise control the volume et sound emitted trom the instrument there is provided a plurality ol groups of sound wave reflectors. Each re- Hector is preferably in the lorm oit an elongated llat member 2O having bevellcd lateral edges and pivotaltv mounted to rotate about its longitudinal axis (sce Figure 2), and having a facing 5l et metal on its inner surface. Each reflector is provided with an arm 21 rigidly fastened thereto and the arms ot the upper groups of reflectors are pivotally interconnected by connecting rods 22. rlhe arms of the lower group are connected to a connecting rod 23. One of the arms in the upper group is operatively connected by means of a link 2d to a radial arm on a rotatable sha lt 25 extending through the casing 11 and mounted in spaced bearings 26, 26 secured to the casing. A collar 27 is mouiited on the shaft 25 tor maintaining the shaft in fixed longitudinal relation with respect to the bearings 2G. The lower connecting rod 23 is operatively connected to the shaft 25 by means ot a link 28 extending trom the connecting rod 23 to a second radial arm .29 allixed to the shaft 25.

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For rotatingr the shaft at will, there provided an operating mechanism including an arm secured to the shaft and pivotallv connected with one end ol a link 251 the other end of which secured to one arm of a bell crank lever 32. The bell crank lever 32 is pivotally mounted as at 33 on a. bracketl 34 depending from the pianocasing` 11. The other arm o'l the bell crank lever 32 is engaged by a if'ertically reciprocatingr rod 35 communicating with one pedal 3G ot' a group of pedals mounted in a pedal block 37, the other pedals and 39 ot which are connected to any desired portions ot the piano such as the sostenuto and loud pedal action as may be desired. A leaf spring et() is secured to the casing o't the piano and engages the bell crank lever 32 tor normally maintaining the bell crank lever and the associated parts in the position shown in Figure 2.

Each ot' the arms l21 of the upper grou) is of a different length, and extends at a di ferent angle with respect to the plane of the respective closure. A predetermined movement of the upper rod 22 thus imparts a dill'erent degree of angular movement to the arms connected thereto and thus rotates the dilferent `reflectors to different degrees ot opening.

In operation, the keys of the piano are employed in the usual way for vibrating the strings by percussion. The sound wave reflectors are normally open and the damped comprcssional waves produced within the casing are emitted therefrom. The metal lining serves to lorm resonating chambers within the piano casing, one chamber being over the sounding board, and the other underneath.

lVhen it is desired to modulate .the sound emitted the foot pedal 3G is depressed, thereby elevating the rod 35 and rotating the bell crank lever 32 in a counter clockwise direction against the pressure of the spring l0. This causes the link to be moved towards the right ot' Figure 2 thus rotating the arm 30, the shaft 25 and the radial arms thereon in a counter clockwise direction as seen in Figure The links 2l, 28 are thus moved to the right, together with the connecting rod 23 and the upper connecting rods `22.

The lower group of sound Wave reflectors having arms 21 of substantially the same length, are closed at -a uniform rate, but the upper group having arms of different lengths are closed at various rates. Thus the reflector at the extreme left of Figure l, i. e., adjacent the bass strings of the piano, are closed at the slowest rate, while 'the reflector at the .extreme right, i. e., adjacentthe treble strings, are closed at the fastest rate. The intermediate reflectors close at rates intermediate these extremes. The anguiar positions of the arms 2l of the upper reflectors are such that when the pedal 36 is fully depressed, all of the reflectors are lully closed. Upon releasing the pedal, the reflectors are restored to normal by the action ol the spring 40.

Thus it will be seen that there is provided a musica-l instrument in which the musical tones of high pitch, which are produced by strings of relatively small mass, 'with proportionally small energy, are differently controlled from notes of low pitch and having greater energy. The arrangement illustrated is intended to restrict the emission ot' the stronger tones to a greater degree than in the case of the 'weaker tones. A more even depth of tone can thereby be produced.

The invention upon which this application is based is broader than the .specific embodiment shown and described for the purpose of illustrating at least one of the ways in 'which it may be employed. The scope of the invention is therefore to he understood as not being limited l) the present 4specific description. I inten no limitations other than those imposed by the claims.

What is claimed is:

l. In a musical instrument of 'the percussive type, the combination with tuned strings, of a casing 'having oppositely disposed apertures, contrellable closures for said apertures arranged in groups, and means for actuating the closures of at least one of said apertures at a speed relatively dill'erent from the speeds of the others of the closures.

2. In a musical instrument of the percuss'ive type, the combination with tuned strings, of a casing having an aperture for the emission of sound, and a plurality of contri'illable closures for said apertures, each of said closures being arranged to be operated atrelatively different speed.

3. In a musical instrument of the percussive type, the combination with vibratory elements of relatively different mass, of a casing having an aperture for the emission of sound produced by said elements, a plurality of closures positioned in said aperture, and means for simultaneously actuating said closures by different amounts whereby different sound emitting spaces are obtained.

fl. In a musical instrument of the percussive type, a plurality of hammers, strings arranged to be set into vibration by the impact thereon of said hammers, a plurality of keys for actuating said hammers respectively, a casing for the instruments, said casing having an apeitui'e for the emission of sound therefrom, a plurality of movable sound wave reflectors positioned in said aperture, each comprising a centrally pivoted member, an arm of predetermined length mounted on each member, the arms ist;

of the different reflectors being relatively different in length, and operating means` joining` the outer ends of said arms for rotating said reflectors at relatively different rates of speed.

5. A sound Wave control system comprising a plurality of centrally pivoled sound wave reflectors, each having' an operating` arm extending outuf'ardly tlierefrom at an angle, the arms of' said reflectors being` relatively different in length respectively and extending at relatively different angles, and

operating means for said reflectors comprising rods interconnecting the outer ends ol said arms arranged so that in one position said reflectors effectively suppress Sound Waves, and upon predetermined actuation of said operating means said reflectors are r0- tated to relatively different angular positions.

Signied at Rome, in the Province oil' Romo and Kingdom of Italy this second day ol' March A. D. 1927.

J Ol-IN HAYS HAMMOND, Jn. 

